This invention relates to improvements in mechanical joints, and more particularly concerns a hinged self-locking mechanical center joint for joining columnar structures. This invention is especially useful in packing columnar members for transportation into outer space and for assembling columnar structures in outer space with remotely controlled mechanical devices.
The Space Shuttle Transportation System is being developed by the National Aeronautics and Space Administration to provide the capability of placing a relatively large payload into outer space. This system will make feasible the construction of large structures in outer space. However, even though the Space Shuttle represents an improvement in orbital payload capability, it is presently limited to a cargo bay fifteen feet in diameter and sixty feet in length. Because of this limitation on cargo space and because transportation of construction materials into outer space is expensive compact storage is essential.
In an earlier invention (Bush, U.S. Pat. No. 4,259,821), lightweight, hollow body half-columns for use in constructing large truss structures were disclosed. These half-columns are compactly stored by stacking them one inside another and may be transported efficiently. In Bush, (U.S. Pat. No. 4,259,821), the half-columns are stored separately and joined manually by the astronauts immediately prior to use. This method, however, burdens the astronauts with the difficult task of connecting the half-columns together under spatial vacuum conditions. The present invention is designed to provide a method of both automatically joining these half-columns and allowing them to be compactly stored. The present invention permits the half-columns disclosed in Bush (U.S. Pat. No. 4,259,821) to be stored one inside another after they are joined together by providing a connecting joint that automatically rotates the half-columns together and locks them into place once they are removed from their storage position. Existing joints are incapable of simultaneously performing these functions.
Most existing mechanical joints are not self-locking, i.e., they must be locked manually and are not feasible for use in outer space. Existing self-locking mechanical joints result in either single point contact locks or unevenly spaced multiple point contact locks. These joints are not locked evenly about their mating faces. Therefore, they are of uneven strength and are not competent to withstand all type of anticipated loads. For example, a hinged joint that is locked at a single point opposite the hinge will not be competent to withstand a large bending load applied in the plane perpendicular to the plane containing the lock and hinge. Such a joint is not acceptable for use in a structural column that might be subject to such a bending load. Because the structural columns anticipated for use in spatial truss structures might be subjected to this type of load, an unevenly locked joint is not acceptable for use in such a truss structure. Other existing center joints either have nonsymmetrical hubs or have hubs with obstructed interiors and when used to join pairs of hollow body half-columns, do not allow the pairs of the half-columns to be stacked one inside the other.
Accordingly, it is an object of this invention is to provide a self-locking mechanical joint that allows joined pairs of half-columns to be stacked one inside the other and thus facilitate compact storage and transportation into outer space.
Another object of this invention to provide an evenly locked mechanical joint that is competent to withstand all type loads.
Yet another object of this invention is to provide a hinged self-locking mechanical center joint for joining pairs of half-columns which automatically rotates a pair together and locks when released from transportation position.
A further object of the present invention is to provide a mechanical joint having evenly spaced multiple contact points providing spring-urged wedging joint locking capability.